A method for preparing chromosomes from peripheral blood of the mouse.

A modified Triman et al. (1975) procedure for preparing metaphase chromosomes from mouse peripheral blood is described. Modifications include: isolation of white blood cells using a ficoll-hypaque gradient; seeding cultures with a known concentration of leucocytes such that the PHA/cell concentration can be controlled for optimum stimulation through 72 h with no media change; and visual monitoring of cell growth to determine when there should be sufficient numbers of dividing cells for harvest and thus eliminate unnecessary harvest of non-productive cultures. We have found this modified procedure to be highly reproducible with the final 0.5 ml fixed cell suspension yielding 50-75 quality metaphase spreads per drop.